1. Field of the Invention
This invention is in the field of jet igniters for internal combustion engines of the piston and cylinder type, wherein a burning jet of fuel air mixture is used to ignite the principal air fuel mixture in each engine cylinder.
2. Description of the Prior Art
In those internal combustion engines of the piston and cylinder type which utilize fast burning principal air fuel mixtures, an ordinary electric spark, fired at the optimum time in the engine cycle, is adequate to accomplish the ignition needed to start the rapid burning of the principal air fuel mixture. When, however, a slow burning principal air fuel mixture is utilized, a jet igniter is frequently needed so that the burning can be completed in a reasonably short time interval. The jet igniter creates ignition sources of burning igniter gases distributed widely throughout the engine combustion chamber. As a result many burning zones are created and the total burn rate of the slow burning principal air fuel mixture becomes adequate to complete the burning thereof in a short time.
Examples of slow burning principal air fuel mixtures for engines are as follows:
1. Very lean gasoline in air mixture utilized to reduce exhaust emissions;
2. Very lean natural gas in air mixtures;
3. Producer gas in air mixtures utilized with some coal burning engines;
Prior art jet igniters have comprised the following elements:
1. A mixing chamber, separate from and smaller than the principal engine combustion chamber and connected thereto by a nozzle flow passage;
2. Means for introducing igniter fuel and air into the mixing chamber to create an igniter air fuel mixture therein;
3. Spark igniter means for igniting the igniter air fuel mixture in the mixing chamber;
Ignition and burning of the igniter air fuel mixture in the mixing chamber causes a pressure rise therein and this pressure increase forces the burning igniter air fuel mixture, through the nozzle flow passage, into the principal engine combustion chamber. This jet of burning igniter air fuel mixture then ignites the principal air fuel mixture at many places distributed throughout the engine combustion chamber. Prior art jet igniters have differed principally in the geometry of the mixing chamber and nozzle flow passage and in the means for introducing igniter fuel and air into the mixing chamber prior to ignition therein.
The igniter jet created by these prior art jet igniters is of short duration being limited by the burning time of the igniter fuel air mixture in the mixing chamber and the flow rate of the jet out through the nozzle. If longer jet duration is sought by use of a smaller diameter flow nozzle, nozzle maintenance problems result due to high velocities of flow of very hot burning gases.
A jet igniter apparatus, wherein the duration of jet flow could be adjusted as needed, and wherein the burning of the jet commenced beyond the jet nozzle, and inside the engine combustion chamber, would be a desirable improvement over these prior art jet igniters. Jet nozzle maintenance problems would be avoided, since the gases flowing therethrough would not yet be burning.
3. Definitions
The term piston internal combustion engine is used herein and in the claims to mean an internal combustion engine of the piston and cylinder type, or equivalent such as the Wankel engine type, and comprising:
At least one combined means for compressing and expanding gases, each combined means comprising an internal combustion engine mechanism comprising a variable volume chamber for compressing and expanding gases, and drive means for driving said internal combustion engine mechanism and varying the volume of said chamber through repeated cycles.
Each variable volume cycle comprises a compression time interval, when said variable volume is sealed and decreasing, followed by an expansion time interval, when said variable volume is sealed and increasing, these two time intervals together being a compression and expansion time interval.
Each combined means for compressing and expanding further comprises intake means for admitting reactant gases into said variable volume chamber prior to each compression time interval and exhaust means for removing reacted gases from said variable volume chamber after each expansion time interval.
Each variable volume cycle further comprises an exhaust time interval, when said variable volume is opened to said exhaust means, followed by an intake time interval, when said variable volume is opened to said intake means, these two time intervals being an exhaust and intake time interval; said exhaust and intake time interval following after a preceding expansion time interval and preceding a next following compression time interval. For a four stroke cycle piston internal combustion engine each separate time interval occupies approximately one half engine revolution and thus one stroke of the piston. For a two stroke cycle piston internal combustion engine the expansion time interval together with the exhaust time interval occupy approximately a half engine revolution and one piston stroke, and an intake time interval followed by a compression time interval occupy the next following half engine revolution and piston stroke.
A piston internal combustion engine further comprises a source of supply of reactant gas containing appreciable oxygen gas to each intake means, frequently air, or air containing fuel added thereto outside the variable volume chamber, and in an intake manifold. A piston internal combustion engine further comprises a source of principal engine fuel and means for delivering this fuel into the variable volume chamber.
Each cycle of the variable volume chamber further comprises a potential combustion time interval comprising that portion of the compression and expansion time interval during which principal engine fuel and reactant gas containing appreciable oxygen gas are both present within the variable volume chamber.
When this mixture of principal engine fuel and reactant gas containing appreciable oxygen gas, is ignited, a burning time interval occurs, preferably commencing late during the compression time interval, and ending early during the expansion time interval. Various types of igniters can be used to initiate burning of such fuel air mixtures such as spark igniters, glow plugs, or compression ignition.
Each bubble jet igniter of this invention comprises: an air displacer piston and cylinder enclosing an air displacer volume; an igniter fuel displacer piston and cylinder enclosing a fuel displacer volume; and these force air and igniter fuel together in an enclosed bubbleizer chamber, wherein a fluid composition is thusly created, comprising air bubbles within the liquid fuel. The air and fuel displacer pistons are each separately driven by larger area driver pistons, in driver cylinders, acted on by the pressure in the variable volume chamber. The fluid composition created in the bubbleizer chamber passes through an enclosed enrichener chamber, where evaporation of liquid fuel creates a stratified air fuel mixture within each bubble. From the enrichener chamber the fluid composition is forced through an igniter jet nozzle into the combustion chamber portion of the variable volume chamber. When within the engine combustion chamber, the stratified air fuel mixture within each bubble is ignited, as by compression ignition, or by an electric spark located near the igniter jet nozzle exit in the combustion chamber. The consequent burning of the bubble mixtures increases the pressure therein, and subsequent bubble expansion disperses burning fragments of liquid fuel throughout the engine combustion chamber. In this way many additional ignition regions are created, distributed throughout the engine combustion chamber. As a result, rapid combustion can be achieved, even when using slow burning principal fuel in air mixtures, and this is one of the principal beneficial objects of this invention.
Several valves, with actuators, and a valve controller are used, to turn on the bubble jet igniter at the desired start of the burning time interval, to turn off the bubble jet igniter, and to replenish the air and igniter fuel in the displacer volumes when the bubble jet igniter is turned off.